Q: How can I use Goldie to create a compiler?

A: This is not an easy task no matter what parsing tool you use.
To get started, see the Never Used a Parsing Tool? page which contains an
overview of everything involved in creating a full compiler.

In summary:
Use Goldie to implement a lexer/parser (see Goldie Overview and
the Beginner's Tutorial), and then,
just as with any other parsing tool, you'll have to do your own
semantic analysis on the resulting tree, and then implement a compiler backend.

Q: Can Goldie parse the D language?

Q: I'm getting "Ambiguous symbol" errors!

Q: This project sounds very similar to Gazelle.
What's the difference, and which one is better?

A: GOLD/Goldie and Gazelle are
both members of a new class of generic parsers that focus on fully-reusable
grammars that aren't tied to any particular host language. They both
accomplish this by completely separating the grammar from the parsing engine.

Both systems have their pros and cons, and which one's better is up to you.
They're both evolving, so limitations on both sides are likely to change.
Here is a comparison (disclaimer: based on my admittedly limited knowledge of Gazelle)
so you can decide for yourself: